The present invention relates to a golf club head having a mass-adjusting weight inserted into the inside of a hosel portion and a method of manufacturing the same, more particularly, to a golf club head that permits strongly fixing a mass-adjusting weight even where the inner surface of the hosel portion is inversely tapered such that the inner diameter of the hosel portion is greater on the side of the bottom than on the side of the opening and a method of manufacturing the same.
In assembling a golf club, a golf club head is generally required to exhibit a high accuracy in mass, making it necessary to correct an error of mass that is generated in the casting step or the like. As a means for adjusting the mass of a golf club head, a mass-adjusting weight is inserted into the inside of a hosel portion.
The mass-adjusting weight is simply dropped into the inside of the hosel portion. Alternatively, a thin flange is formed in a peripheral portion of the weight, and the flange is pressed against the inner surface of the hosel portion so as to be crushed when the weight is inserted into the inside of the hosel portion, thereby obtaining a caulking effect. However, the caulking effect cannot be obtained in the case where the inner surface of the hosel portion is inversely tapered such that the inner diameter of the hosel portion is larger on the side of the bottom than on the side of the opening, making it impossible to fix strongly the mass-adjusting weight to the hosel portion. If the fixing of the mass-adjusting weight is insufficient, an adhesive for bonding a golf club shaft to the hosel portion leaks into the inner portion of the club head to be solidified. The solidified adhesive is dropped as a small lump into the inner portion of the club head when a golf ball is hit by the golf club. Also, the weight itself is vibrated within the hosel portion to generate noise when the golf club is swung or when a golf ball is hit by the golf club.
The object of the present invention is to provide a golf club head that makes it possible to fix strongly a mass-adjusting weight even where the inner surface of the hosel portion is inversely tapered and a method of manufacturing the same.
To achieve the above-noted object, the present invention provides a golf club head in which a mass-adjusting weight is inserted into the inside of a cylindrical hosel portion, characterized in that a flange that can be deformed in a radial direction of hosel portion is formed in a peripheral portion of the weight and the diameter of the flange is increased to fix the weight to the hosel portion.
Since a flange that can be deformed in a radial direction of the hosel portion is formed in a peripheral portion of the weight and the weight is fixed by increasing the diameter of the flange, it is possible to fix strongly a mass-adjusting weight even where the inner surface of the hosel portion is inversely tapered. Particularly, if an annular groove extending in a circumferential direction of the hosel portion is formed in the flange, the flange can be deformed easily in a radial direction of the hosel portion.
The present invention also provides a method of manufacturing a golf club head, characterized by comprising the step of forming a flange that can be deformed in a radial direction of the hosel portion in a peripheral portion of a mass-adjusting weight, the step of inserting the foregoing weight into the inside of a hosel portion of a golf club head, and the step of applying a pressurizing force to the flange in an axial direction of the hosel portion to increase the diameter of the flange portion and, thus, to fix the weight to the hosel portion by caulking.
The weight can be fixed by caulking by inserting the weight into the inside of the hosel portion of a golf club head, followed by applying a pressurizing force to the flange in an axial direction of the hosel portion to increase the diameter of the flange. The particular caulking fixation can be achieved easily by using a caulking tool that can be inserted into the inside of the hosel portion and can abut against the flange.